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Title: Heathkit Mohawk Receiver RF alignment information Post by: ns7h on June 19, 2023, 09:09:43 AM Does anyone have a resource for the RF alignment of the Heathkit Mohawk? The receiver kit had the RF deck prewired and aligned and no information regarding which coils are antenna, oscillator, and mixer on the deck is in the manual. I guess I could trace it out with some difficulty, so I am seeing if someone has done this already or has a reference that would save some time or should I just let it go. No problem on most bands, but 40 meters is off frequency about 150 Khz.
Thanks in advance - NS7H Title: Re: Heathkit Mohawk Receiver RF alignment information Post by: K4NYW on June 19, 2023, 09:29:52 AM There was a separate manual for the 100-139 tuner assembly - fortunately it is included here -
https://www.vintage-radio.info/download.php?id=912 Title: Re: Heathkit Mohawk Receiver RF alignment information Post by: ns7h on June 19, 2023, 03:57:49 PM Got it!!! Exactly what was needed.
Thanks again - NS7H Title: Re: Heathkit Mohawk Receiver RF alignment information Post by: WQ9E on June 22, 2023, 08:52:17 AM The most important thing to remember when operating the RX-1 Mohawk is that IF gain control on the front panel should not be anywhere close to maximum. It was put there by Heathkit so that the operator could optimize performance for different conditions but unfortunately many users turn it full clockwise and then complain about their noisy and overload prone receiver. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Many sets have IF gain pots that are set as part of alignment and in a properly operating set, the IF gain is never run at max. The same holds true for the control on the Mohawk. And ignore that article about the mistake Heathkit made in not applying AGC to the IF strip, Hallicrafters knew what they were doing with their SX-101 in not applying AGC and Heathkit followed their lead. The Miller Effect refers to the change in tube internal capacitance as bias is varied, that is useful when you are building a frequency modulator stage but changing internal capacitance is the last thing you want in a highly selective IF strip which is why AGC isn't applied in the low frequency IF strip. Properly operated, it is a nice set and it should be because it was very heavily influenced by the excellent line of Hallicrafters 50 Khz. IF receivers but operated incorrectly it lives up to its much undeserved reputation as a dog. I have a pair of them integrated into Heathkit stations of the era. Rodger WQ9E |